Grinding machine feeding mechanism



Deco w, 1935. H. A. SILVEN GRINDING MACHINE FEEDING MECHANISM Filed May 5, i953 "Patented Dec. 10, 1935 PA OFFICE.

cnmnnvo MACHINE FEEDING MECHANISM Herbert A. Silven, Worcester, Mass., assignor to- Norton Company, Worcester, Mass., a corporationof Massachusetts Application May 5, 1933, Serial ndcsases I '6 Claims.

This invention relates to grinding machines, and more particularly to a hydraulically operated grinding wheel feeding mechanism.

Heretofore, it has been common practice in the grinding field in cylindrical grinding operations to move either the work or the wheel relatively toward and from the other member to produce the desired grinding action and reduce the work piece to the required size. .Such feeding movements have been effected bymanually controlled feeding mechanisms, as well as power operated mechanisms, such as electrically, mechanically or hydraulically driven mechanisms. To obtain accuracy in regard to size of the finished work piece, as well as quality of finish, it has been desirable to feed the wheel first at a rapid rate until the wheel and work engage each other, then at a slow rate or grinding feed to reduce the work piece to the required size, and then to definitely limit the forward feeding movement of the grinding wheel byv a stopping device which holds the wheel and work in a fixed position relative to each other for a flnishgrinding operation to reduce the work piece to a. predetermined size. In previously devised feeding mechanisms, this has been accomplished by power actuated mechanisms which moved the wheel slide to a definite stop, and by manually operated devices, whereby the feed wheel was turned at a rapid rate until the wheel engaged the fed rapidly relatively toward and fro work, then at a slower rate to produce the desired grinding feed; and finally stopped to allow the wheel and work to remain in grinding contact, with no relative feeding movement between the two members, such as is shown in the patents to Norton Nos. 1,653,922 and 1,416,054.

It is the primary object of this invention to provide a hydraulically actuated wheel feeding mechanismby which the work and wheel may be each other. first at a rapid rate and then at a slower rate for finish grinding'the work piece. It is another object of this invention to provide a wheel feeding mechanism having a manually rotated feed screw mechanism to permit adjustment of the wheel position, a fluid pressure piston and cylinder to cause a rapid approaching and receding movement between the wheel and worhand asecondary mechanismto modify the approaching movement and produce a slow grind-.

in feed. 4

It is still another object of this invention to provide a feeding fol-moving a. wheel slideby means of a fluid pressure system includ-' move a rotatab the work, and a secondary self-contained fluid pressure system having a piston arranged in axial alignment with'the first named piston and cylinder to modify the movement caused by'the first cylinder and produce a slow, uniform grinding feed to finish grind the work.

It is still a further object of this invention to provide a wheel feeding mechanism in whicha fluid pressure piston and cylinder are provided to move the wheel slide toward and from the work, and a dash pot pistom is slidably mounted on a projecting portion of the piston rod surrounded by a dash pot cylinder which is arranged to modify the feeding movement causedpby said piston and cylinder to produce a slow grinding feed.

Other objects will-be apparent from the following disclosure. Qne embodiment of this invention has been illustrated in the drawing, in.

proved fiuid pressure wheel feeding mechanism-e Fig. 2 is a fragmentary sectional view, on an enlarged scale, showing the dash pot mechanism located at the right-hand end of Fig. 1; and

Fig. 3 is a fragmentary cross-sectional view, taken approximately on the line 3-3 of Fig. 2.

This invention comprises a grinding wheel feeding mechanism for causing a relative approaching and receding movement between the grinding wheel and a rotatable work piece, which is arranged so that the wheel feeding movement will take place first at a rapid rate to bring the work and wheel into engagement with each other, thenat a slow rate to obtain the desired grinding action between the wheel and work to reduce the work in size, and finally stopping the wheel feed by means of a positive stop and allowing the wheel to spark-out or finish grind the work, during which time there is no relative feeding move-' ment. A fluid pressure system serves to cause a rapid relative approaching and receding movement between the work support and the grinding wheel, and a secondary self-contained fluid pressure system serves to modify said rapid relative 4 approaching movement and cause a slow uniform grinding feed. An adjustable stop serves to limit the forward feeding movement of the grinding wheel and allows the wheel and work to remain in contact with each other to finish grind the 7 work and to reduceit to a predetermined size,

In the preferred construction, the feeding mechanism comprises a. fluid pressure actuated piston in axial alignment with and arranged to le feed screw endwise so as to feed 5 a the wheel slide II and meshing with a rotatable" cross feed screw 26 which is supported in bear-- ings 21 and 28 respectively. in the base III. A

manually operable feeding mechanism is provided a grinding wheel and a work blank relatively toward each other at a rapid rate. A secondary self-contained fluid pressure system including a dash pot also in axial alignment with the feed :screw is efiective, ai'ter a predetermined rapid feed, to cause a slow feeding movement of the grindingwheel, and an adjustable stop associated with the dash pot positively limits the ap-' proaching movement between the grinding wheel and the work feed. The invention is equally applicable to either of the standard typesof cylindrical grinding machines, in one of which the work is mounted on a slide movable toward and from the periphery of a stationary-grinding wheel, and in the other the rotatable grinding wheel is mounted on a wheel slide arranged for a transverse feeding movement relative to a stationary work support. l

As illustrated in the drawing, a inding machine is provided having a base "I, which is provided with a wheel slide II slidable transversely on suitable ways l2. A rotatable grinding wheel I3 is mounted on a wheel spindle M which is supported for rotation in suitable bearings (not shown) on'wheel slide H. The grinding. wheel may be rotated from any suitable source of power, either by means of a driving belt from an overhead countershaft or, as is the usual case in the modern grinding machine, driven from; an electric motor either mounted withinthe base or on the wheel slide. A work piece I5 is rotatably mounted on a headstock I6 and rootstock (not shown) which are in turn supported on a longitudinally movable table II. The. table IT is supported by a V-way l8 and a flat way I! on the base Ill and serves to position the work piece relative to the operative face of the grinding wheel. f 1 v I To produce a relative feeding movement between the grinding wheel I3 andthe work piece IS, a suitable feeding mechanism'is provided which may comprise a half nut depending from comprising a manuallyoperable micrometer feed wheel 29, such as that shown in the prior patent mechanism have been omitted, since they are not to Norton No. 762,838 dated June 14, 1904. De-

tails of the micrometer adjustment of the feed part'of the present invention. For further reference to detailed construction of the micrometer adjusting device. reference may be had to the above-mentioned patent. The feed wheel 29' is rotatably mounted on a stud 30 which also sup- 'ports a gear 3| meshing with a gear 32 mounted on the outerend of a rotatable shaft 33. The shaft 33 is supported in bearings 36 and in the base Ill, and is slidably keyed by means of'a key 31 to a reduced portion 38 of the feed screw 26. It will be readily apparent from the foreing feed.

going disclosure that rotation of the manually operable feed wheel 29 transmits motion through gears 3| and "and shaft 33 to rotate the .cross feed screw 26 andcause a relative approaching or receding movement between the work piece l5 and the grinding wheel l3. The mechanism above described serves to manually'adjust the position of the grinding wheel relative to thework piece' and may, if desired, be utilized to cause a; grind- In the preferred construction, however, a s'uitable fluid pressure.mechanism is provided which is arranged tomove the slide so asto cause either each end of the piston and projects through the 1 ends of said cylinder. The rod 42 is connected at its outer end to the rear end of the feed screw 26. A cylindrical slidably mounted member 45 is arranged to slide within a cylinder 46 and is slidably keyed thereto by means of a key 4'1. The 15 slide 45 carries the bearing 28 which in turn supports the rear end of the feed screw 26. The piston rod 42 is operatively connected to move the slide 45.

A fluid pressure system is provided including a go reservoir 50 within the base In and a pump 5| which pumps fluid'through a pipe 52 and a pipe 53 through a reversing valve 54 into the cylinder 40. A suitable relief valve 55 is provided in the pipe line 53 which is arranged so that excess pres- 5 sure in the system will by-pass fluid through a pipe 56 into the reservoir 50.

The reversing valve 54, of the balanced piston type, is provided with a valve piston 51 which is preferably manually controlled by means of a go lever 58 pivotally mounted on a stud 58 and connected by a rod 60 with the valve piston 51. In the position of the valve piston 51, as illustrated in Fig. 1, fluid under presssure .is admitted through the reversing valve into a cylinder chamber 60 to move the feed screw 26 bodily toward the left, and cause a rapid approaching movement of the grinding wheel 13 relative to the work piece IS. The parts illustrated in Fig. 1 are shown with the work and wheel in grinding ena gagement with each other. During the "ap-' proaching or infeeding movement, fluidls exhausted from a cylinder chamber 6l,'through the reversing valve 54, a pipe 62, into the reservoir II. When it is desired to cause a rearward move- 4| ment of the grinding wheel slide, the operator moves the'manually operable control lever 58 in a clockwise direction, as viewed in Fig. 1, so

"as to admit fluid under pressure from the pipe 53 into the cylinder chamber 6| to cause an endu wise movement of the feed screw 26 toward the right, as viewed in Fig. 1.

Dash pot control It is desirable to provide a suitable mechanism I for'reducing the rapid approaching movement to a slow grinding feed when the grinding wheel has been brought into engagement with the work piece. In the preferred construction, a secondary self-contained fluid pressure system is pro- Q vided which, as illustrated, comprises a dash pot having a dash pot piston 66 arranged in axialalignment with the feed screw and preferably so constructed and arranged that the dash pot piston 66 is slidably mounted on an extended I portion 61 of the piston rod 42. When the wheel is fed toward the work, a rapid approaching movement is obtaineduntil a sleeve 68, which surrounds the rod 61, engages the end of the dash pot piston 56 which serves to modify the ap- 1o proaching movement of the grinding wheel so as to reduce the feed to a proper grinding feed. To

facilitate adjustment .of the sleeve 68 relative to the piston rod portion i'lyan internal thread.

on the sleeve engages a threaded portion II on the rod 61 and may be located in adjusted position by a lock nut 69. A spring within the dash pot piston 65 and surrounding the rod 61 serves to return the dash pot piston to its initial or rearward position during the separating movement between the wheel and work. During the idle return movement of the dash pot piston 66, oil is drawn through a ball check valve 14 into a dash pot chamber 12 from aself-contained reservoir T3 which is formed integral with the dash pot cylinder 65, so that the dash pot is then in condition for the next grinding operation.

The rearward or idle stroke of the dash pot piston 66 under the influence of the spring 10 is limited by a pin 8!, fixed to the piston and projecting through the dash pot cylinder head, which engages an adjustable stop nut 82.

When the movement of the piston 4| starts to move the dash pot piston 66 toward the left, as

viewed in Fig. 1, the oil escapes slowly from the chamber 12 through a needle valve 15, a port 16 and back to the reservoir 13. The forward grinding feed continues until. the adjustable sleeve 80 engages the end of the dash pot cylinder 65, thereby positively limiting the approaching movement between the grinding wheel and the work.

The operation of this mechanism will be readily apparent from the foregoing disclosure. The operator places the desired piece of work in the machine and moves the control lever 58 into the'position as illustrated in Fig. 1 to cause a rapid approaching movement of the grinding wheel toward the work piece. This approaching movement of the wheel toward the work con-, tinues until the sleeve 58 engages the dash pot piston 66 which, as previously described, serves to modify the rapid approaching movement of the stopping of the infeed and the rate of the grinding infeed may be regulated. By utilizing the manually operable feed wheel 29, the grinding wheel 20 may be manually positioned relative to the fluid pressure system in setting up the machine for a given operation.

Having thus described the invention, what is claimed as new and desired to be secured by LettersPatent is:

l. A grinding machinecomprising a base having a work. support and a rotatable grinding wheel thereon, a transversely movable wheel slide 1hr moving said wheel toward and from the work, a fluid pressure system including a piston and cylinder interposed between the base and wheel slide and arranged to cause a transverse movement of said slide, a piston rod operativelyconnected to move the slide and cause a rapid approaching and receding movement between the wheel and work, and a secondary fluid pressure s stem including a dash pot piston slidably mounted on said piston rod, a dash pot cylinder surrounding said dash pot piston and fixed to the end of said first cylinder and an adjustable stop carried by said rod which isarranged to en-v gage and move said dash pot piston so as to modify the feeding movement of the slide caused by the first named piston and produce a slow grinding feed.

2. A grinding machine comprisinga base hav- I ing a work support and a rortatable grinding wheel thereon, a transversely movable wheel slide for moving said wheel toward and from the work, a manually rotatable screw rotatably supported in said base and operatively connected to 5 move the slide, a fluid pressure system including a piston and cylinder interposed between the base which is arranged to modify the'feeding-movement of the slide caused by the first named piston and produce a slow grinding feed.

3. In a grinding machine, a feeding mechanism for a grinding wheel comprising a base, a movable wheel slide, a fluid pressure system includ- I ing a cylinder fixed to the base, a piston slidably mounted within said cylinder, a double end piston rod extending through opposite ends of 'said cylinder, connections between one end of said piston rod and the slide to move the slide and cause a rapid approaching and receding movement of the wheel, a secondary fluid pressure system 3 including a piston slidably mounted on the other end of said piston rod, a dash pot cylinder surrounding said second piston and fixedly mounted onsaid first cylinder, a valve arranged to regulate the exhaust of fiuid from said dash pot cylinder, and an adjustable member on said piston rod arranged to engage and move the dash pot piston so as to modify the feeding movement of the slide caused by the first piston and cause a slow grinding feed. 4o

4. In a grinding machine, a feeding mechanism for a grinding wheel comprising a movable wheel slide, a nut and screw mechanism arranged to move the slide, a fluid pressure system including a cylinder fixed to the base, a piston slidably mounted within said cylinder, a double end piston rod extending through opposite ends of said cylinder, non-rotatable connections between one end of said piston rod and the feed screw operatively connected to the feed screw to move the screw endwise and cause a rapid approaching and receding movement of the wheel, a secondary fluid pressure system including a piston slidably mounted on the other end of said piston rod, a dash pot cylinder surrounding said second piston '55 and fixedly mounted on said first cylinder, a valve arranged to regulate the exhaust of fluid from said dash pot cylinder, and an adjustable mem-' ber on said piston rod arranged to engage and move the dash pot piston so as to modify the on feeding movement of the slide caused by the first piston and cause a slow grinding feed.

5. In a grinding machine, a feeding mechanism for a grinding wheel comprising a base, a movable wheel slide, a fluid pressure system in- 5 eluding a cylinder, mounted on said base, a piston movable within said cylinder, a piston rod ex tending from each end of said piston and projecting through the ends of said cylinder, connections between one end of said piston rod and7o the slide to move the slide and transmit an appreaching or receding movement to the grinding l wheel slide, a secondary fluid pressure system including a dash pot piston slidably mounted on the other end of said piston rod, a dash pot cylinder surrounding saidpiston and fixed tothe end of said first cylinder, a self-contained reservoir integral with said dash pot cylinder and arranged to supply fluid to said cylinder, a check valve arranged to allow fluid to pass rapidly into the dash pot chamber when the dash pot piston moves rearwardly, a valve effective when the dash pot piston moves forward to regulate the exhaust of fluid from the dash pot chamber, and an adjustable member mounted on said piston rod and arranged to engage the dash pot piston at a predetermined time in the forward feeding movement of the slide to move the dash pot piston and thereby modify the feeding movement caused by the first named piston and produce a slow grinding feed.

6. In a grinding'machine, a feeding mechanism for .a grinding wheel comprising a half nut and a rotatable feed screw, a fluid pressure system including a cylinder, a piston movable within said cylinder, a piston rod extending from each end of said piston and projecting through the ends of said cylinder, connections between one end of said piston rod and the feed screw which are arranged to move the feed screw and transmit an approaching or receding movement to the grinding wheel slide, a secondary fluid pressure system including a dash pot piston slidably mounted 5 on the other end of said piston rod, a dash pot cylinder surrounding said piston and fixed to the end of said first cylinder, a self-contained reservoir integral with said dash pot cylinder and arranged to supply fluid to said cylinder, a check valve ar- 10 ranged to allow fluid to pass rapidly into the dash pot chamber when the dash pot piston moves rearwardly, a valve effective when the dash pot piston moves forward to regulate the exhaust of fiuid from the dash pot chamber, and an adjustable sleeve mounted on said piston rod and arranged to engage the dash pot piston at a predetermined time in the forward feeding movement of the slide to move the dash pot piston and thereby modify the feeding movement caused by 20 the first named piston and produce a slow grinding'feed. I

, HERBERT A SILVEN. 

